3b'0 INTRODUCTION TO CRYPTOQAMIC BOTANY. 



392. The tribe is widely diffused over the world, and several 

 of the species are cosmopolites. The central stemmed or 

 lateral species affect especially warmer climates, but resupinate 

 species are by no means altogether wanting in the tropics. 

 Stereum lohatum in some of its forms is found in all sub -tropi- 

 cal countries ; and if the species be taken in a wide sense, it 

 extends into higher parts of the temperate zones. The species 

 are, however, so closely connected with each other, that it is 

 not always possible to sa}^ what is and what is not distinct. 

 Stereum ruhiginosum, for instance, may either be split into a 

 dozen species, or considered as variable as Fucus vesiculosus. 

 In its wider sense it is found almost everywhere. The species 

 are in general so tough, or so insignificant in point of size, that 

 they are not edible ; and we are unable to point out any other 

 use to which they are capable of being put. 



4. Hydnei, Fi^ 



Fructifying surface inferior or amphigenous, beset with pric- 

 kles, tubercles, &c., but never truly porous, rarely gelatinous. 



393. Thelephora exhibits slight linear elevations or rugosities 

 on its hymenium, but affecting rather a lamellar disposition 

 than that of elongated aculeiform processes. We have, there- 

 fore, so far, nothing leading very immediately to this group, 

 except, indeed, Pldebia is associated with Hydnei, in accord- 

 ance with the views of Fries, an arrangement which is scarcely 

 correct, though I have followed Fries in the system proposed 

 in the vegetable kingdom. In one or two Corticia, indeed, the 

 surface is slightly granulated, and if these granules be a little 

 exaggerated or surmounted by one or more little pointed pro- 

 cesses, it is no great step from Corticium to Grandinia or 

 Kneiffia. Grandinia is, in fact, a Corticium with little 

 decided granular elevations, which never assume the form of 

 teeth or prickles. Kneijjia is a step further in advance, on 

 account of the bristles with which the granules are crowned ; 

 and Odontia makes way rapidly for Hydnum in all its varied 

 forms, resupinate, apodous, lateral, merismoid, and mesopod, 

 with almost every conceivable gradation of substance, colour, 

 and sculpture. We have species, accordingly, strictly mem- 

 branous, others gelatinous, others again fleshy and excellent 



